Self adjusting sunlight reflector



O 2 O 3 CROSS REFERENCE EXAMINER I 1933. J; M. ARTHUYS ET AL 1,938,003 L SELF ADJUSTING SUNLIGHT REFLECTOR Filed Aug. 15, 1930 4 Sheets-Sheet 2 K0 2 0 3 REFERENCE EXAMINER 1933- J. M. ARTHUYS ET AL 1,938,003

SELF ADJUSTING SUNLIGHT REFLECTOR Filed Aug. 15, 1930 4 Sheets-Sheet 3 a4 Fig.7

4/ lk a Patented Dec. 5, 1933 PATENT OFFlCE SELF ADJUSTING sumcnr aarmc'roa Jacques Marie Arthuys, Paris, and Andr Bayle, Vanves, France, assignors, by direct and mesne assignments, to Arthel (Socite dExploitation des Brevets Jacques Arthuys), France, a corporation of France Application August 15,

Paris,

1930, Serial No. 475,520,

and in France September 21, 1929 8 Claims.

Our invention has for its object a self-adjusting sunlight reflector working continuously and indefinitely without a clockwork. It is adapted in particular for the practical commercial illumination by means of sunlight and more generally it allows the distribution and the use of direct solar rays whether visible, infrared or ultraviolet separately or together. rays may, when sunlight is not available, be rem placed by the rays from powerful electric light supplies of high efficiency which are automatically removed as soon as the sun appears. This provides a sort of central illumination for houses and premises.

We have already disclosed a device, for distributing solar rays in obscure premises, which device comprises a sunlight reflector moving with the sun and disposed on the roof of a building so as to send vertically a beam of solar rays into a small courtyard wherein are disposed at varying heights optic systems deflecting each part of the beam for distributing the light into the dark premises considered through the agency of suitable apparatuses. Our invention relates to improvements to such an arrangement as disclosed innF'rench Patent No. 664,430 to Jacques Marie Arthuys.

We will first recall that sunlight reflectors or heliostats are apparatuses which reflect the solar rays in a constant direction however their incident direction may vary according to the position of the sunfor the diiferentfhours of the day or seasons of the year.

All heliostats devised heretofore were adapted for observatory or laboratory use only; on the other hand they were all controlled by clockwork and were provided with mechanical regulators.

Our improved heliostat on the contrary is a 40 practical and commercial apparatus and is not driven by a clockwork but through an auxiliary motor to be described hereinafter. The sun itself controls the movement of the heliostat mirror, whatever the original position of the heliostat may be. In other words, the known heliostats require hand adjustment for taking into account declination of the sun and hand starting and the clockwork controlling them must of necessity be as accurate as a chronometer watch and be continuously supervised. 0n the contrary in the case of our improved heliostat.

(a) It directs itself automatically facing the sun as soon as it appears so as to be able to reilect the sun rays in the desired stationary direction; Y

These solar (b) It follows automatically the complicated movements of the sun (daily movement, variable declination, apparent motion due to atmospheric refraction).

(c) It corrects automatically any defective adjustment or arrangement of parts such as the direction of the pivots and compensates for any play or fiexion etc.

This is accomplished, as explained hereinabove by means of an auxiliary motor comprising mainly differential electric thermometric gas and mercury switches operating under the action of the heat provided by sunlight.

Our invention may be adapted for use with any other apparatuses which have to follow a sideral motion such as an equatorial astronomic glass.

We will describe our invention as applied to a heliostat the mounting of which is the simplest and which we may term an equatorial mounting by reason of its similarity with the mounting of an equatorial astronomic glass.

The automatic control of a heliostat according to our invention is characterized by the fact that the solar rays reflected by the mirror and moving necessarily with reference thereto if the mirror is stationary act on one or more relays sensitive to these rays (for instance a mercury switch provided with a gas-filled space which when heated displaces the mercury so as to control an electric circuit). These relays control one or more motors controlling the movement of the mirror in accordance with the movement of the rays We will first disclose how this automatic control can be effected under the action of the daily movement of the sun on one hand and of its declination on the other through a single mechanism. It should be noted also that the sun not being always visible, there will occur, for instance during the night or when the sun is hidden a shifting of the position of the mirror with reference to that of the sun. To remove this drawback and consequently to make the mirror find the sun, an automatic resetting device to be described hereinafter has been provided.

We have also described a particular form of execution of these heliostat controlling means including the mercury gas-filled switch adapted r1 1; a i

-thesuninsideandplanviews.

I'ig.3isadiagrammaticsideviewofthe arrangament for control by the declination of the sun.

l'ig.4isaplanviewofadetailatalarger scale.

rig. 5 shows diagrammatically in side view an arrangement aflording means for ensuring both controlsv simultaneously.

I'lg.0isasideviewofadetail ofsaidarrangement.

Pig. 7 shows diagrammatically in side view a device for finding the sun when the latter has reappearedsoastoresetthemirrorfacingthe 3 is a plan view of a detail of this device. 0, 10 and 11 are front, plan and side viewsofthesetofauxiliarymirrorsused.

l'ig. 12 is an axial cross-section of the mechanical parts of a practical embodiment of the apparatus according to the precedent diagrammatic showings.

Pigs. 13 and 14 show respectively a mercury gas-filled switch and a contact device working under the influence of heat.

Referring to Fig. l, the sun sends on to the mirror of the heliostat a beam 2 which is reflected paralleltotheaxisoftheearthtowhich the axis 5 of the mirror is held parallel. The reflected beam impinges on the stationary mirror 12 and is reflected thereby along a vertical. The control by the daily'movement of the sun is provided as follows: supposing at a given moment (noon) the plane of the figure containing the sun as W 2? according to the hourly progress of the sun 20. In eflect if at a given moment the stationary mirror 1 is correctly positioned with reference tothesun20.theimageofthesunbeingat this moment at 29 (Fig. 2) slightly to the rear of the elliptic mirror band 31, the movement of thesunwillbringtheimage 29ontheelliptic mirror 31 whereby the reflected image will heat the switch 32: this starts the electric motor 33 which acts on the heliostat mirror and moves it soastobringtheimage29ofthesun'slowlyin front of and away from the mirror segment 31 i. e. back into the position shown in Pig. 2. The

switch 32 receiving no longer the rays reflected by the mirror segment 31, the electric circuit is broken and the motor stops together with the heliostat mirror. The image of the sun begins then to advance again towards the mirror segment 31 and the same movement begins over again whereby the control by the hourly movementofthesunisobtainedbyaseriesofadvances of the mirror. It should be noted that the mirror band or segment having to remain perpendicular to the movement of the image 29 of the sun i. e. with its line of symmetry parallel to the plane of the drawing corresponding to the plane of incidence of the beam on mirror 1, it is necessary for said mirror 31 to pivot at a speed corresponding to that of the mirror holding time shaft 5, as indicated diagrammatically by the dotted line 34-35.

Fig. 3 shows diagrammatically the device through the agency of which the declination movement of the sun 26 controls the mirror 1. The plane of the figure containing, as precedently, the meridian line over which the sun stands at the moment considered, the movement of declination is given out by the arrows 36 or 37 disposed next to the sun. The corresponding movement is shown in plan view in Fig. 4 for the image of the sun 29 which moves as shown by the arrows 38 or 39. In the vertical light beam 2"! are disposed two diflerent parabolic mirror bands 40-41 disposed with their longitudinal lines of symmetry in the plane of the figure and alined with one another. In the plane of the images of the lens 28 given out by these mirrors 40, 41 are disposed two switches 42-43 of the abovedescribed type. These switches are adapted to start in opposite directions a motor 44 which causes the angle e of the mirror 1 with the shaft 5 carrying it to vary.

It is apparent that the daily path of the sun' being followed owing for instance to the arrangement of Fig. 1, the arrangement shown in 1"lgs. 3 and 4 will constrain the mirror to follow the declination of the sun. The reason is that if the image 29 of the sun moving in the direction of the arrow 30 arrives on one of the parabolic mirrors 40. 41 the rays are reflected on one or the other of the switches 42-43 which start the motor 44 rotating in the direction required for the angle eof themirrortovaryinamannersuchaswill return the image over the mirror which has not received it. Obviously the image of the sun will always be held at 45 between the two adjacent mirrors 40-41 whereby the mirror 1 is held in the angular position corresponding to the actual declination of the sim.

The arrangement shown in l'ig. 5 is a combination of those shown in Figs. 1 and 3 allowing a single lens 28, a single group of two parabolic mirrors 40-41, a single pair of switches 42-43 and a single motor 40 to be used for following the sun both along its daily path and in its movement of declination. To this end, the motor 40 controls directly (arrow 4'1) the rotation of the time or mirror carrying shaft 5 and it controls the variation of the angle e (arrow 48) through a clutch 49 the working of which will be disclosed hereinafter. The two switches 42-43 are disposedononehandinparallelinthefeed circuit of the motor 40 whereby when the image 29 of the sum (Fig. 3) comes over one of the mirrors 40, 41 (forming in this case an arrangement equivalent to the single mirror 31 of Figs. 1 and 2) one of the circuit-breakers 42-43 is cloud. and the motor 40 starts rotating in a given direction so as to rotate, through the transmission shown by the arrow 47, the time shaft 5 in the direction required for following the daily. path of the sun. On the other hand the switches or circuit-breakers 42-43 are adapted to feed a set of three coils 50, 51, 52. For instance the switch 42 feeds the coil 50 and the coil 52; the switch names 48 feeds the coils 61 and 62, the latter being fed in opposite directions by the two switches. Consequently when the switch 42 is closed the coils 56 and 52 are excited{ when the switch 43 is closed the coils 51 and 52 are excited; when both,

switches are closed, the coils 50 and 51 are excited.

Underneath the coils so, s1. s: (Fig. 0 is a common armature plate 53 carried by a rotula at 54. This plate may occupy three positions according to the pair of coils which is excited at the moment considered. The armature 53 is carried by a vertical rod 55 the end of which (Fig.

5) controls, through a small rod 56, a lever 5'! pivotally secured at 58 to a stationary point and ca ying at its free end a clutch 49. The motor 46 drives a conical pinion 59 in permanent engagement with two other conical pinions 60, 61 loosely mounted on the shaft 62. The clutch sleeve 49 is mounted on the shaft 62 through a key or balls so as to control its rotation while being allowed a sliding motion along it. According to the position occupied by the armature 53 of the coils 50, 51, 52, the sleeve 49 is either in engagement with the pinion 60 so as to drive the shaft 62 in a given direction or with the pinion 61, soas to drive the shaft 62 in the reverse direction or else with neither whereby the shaft 62 remains stationary. The movement of the shaft 62 is usedas shown atically by the arrow 48, for varying the angle of declination e of the mirror 1.

It is apparent that this arrangement shown in Fig. 5 affords means for following the daily path of the sun by means of the two mirror bands 40 and 41 and the circuit-breakers 43-48 which make the motor 46 start, always in the same direction, for driving the time-shaft 5 whereas, when the motor 46 is operative, the two mirrors 40-41 cooperating with the circuit breakers 42-43 act through the three coils 50-51-52 and the clutch 49 for correcting if required the declination of the mirror.

As explained hereinabove, it is not sufllcient for providing an automatic control of the heliostat by the sun to keep the control working after a nrst adjustment. It is also necessary to use a shifting back device for bringing speedily the mirror to its correct position after a. disappearance of the sun. This device is shown in Fig. 7. It should be noted that, with a heliostat having an equatorial mounting as disclosed, the movements of declination of the mirror 1 during the periods for which the sun may not be apparent are comparatively small and consequently if the time shaft 5 is caused to be properly set, the length of the parabolic mirror bands 40, 41 (Figs. 6 and 5) is yet sumcient for the image of the sun to continue, meeting these bands'when the setting of the time-shaft is effected whereby the normal operation of the device may continue.

To execute this setting of the time shaft, the latter is controlled by a comparatively quick rotating motor 63. In the general electric cir-, cult of the apparatus are disposed a circuitbreaker disposed in an open part where it is always adapted to be struck by direct rays of the sun as soon as the latter appears and in series with another circuit breaker 64, a switch 65 and a motor 63. The switch '65 is carried by the support of the lens 28 described hereinabove to-- gether with an elliptic mirror 66 forming on the switch 65 the image of the lens 96. This switch is heated and breaks the motor circuit as soon asthelens26receivesthebeamofsolar rays the plate 74.

. 8 andformsanimageofthemninfrontofthe mirrcrs4oand4l overthefreepartofthe mirror 66. a

'lheworkingofthedeviceisasfollowszas soon as the sun 26 reappears, the switch 64 is. heated and closes the circuit. The switch 66 which is normally closed, allows the motor 66 tostart. Thetimeshaftisdrivenatacomparatively high speed and the image 29 of the sun (Pig. 6) soon comes near the mirror 66 at 29'. The switch 65 is then heated and breaks the current feeding the motor 63. The time shaft 5 stops in a position such that the normal working of the control means previously described may be resumed.

The opening of the segmental elliptic mirror 66 should be suillcient for the size of the mirror to be great enough for reliably catching the image of the sun at a suitable moment of the rotation of the time shaft, account being taken of the possible change in declination which may occur during the interruption of the solar illumination.

5 as illustrated tica'lly by the arrows 1m 67-68 in Fig. "I.

In Fig. 12 is shown a form of execution oi'all the mechanical parts of this heliostat controlling means. The cylindrical casing 69 directed paralleltotheaxisoftheearthandsecuredtoaggs suitable support carries a hollow time-shaft 70 corresponding to the abovedescribed time-shaft 5. This shaft carries at its free end the mirror 1 and is inserted inside a shaft '11 the other end 72 of which is carried by the bearing 78 12s of the support with the interposition of a ball bearing. A plate'74 secured to the tube 70 carries the electric motor '15 serving to provide the movement corresponding to the daily movement of the sun. The transmission is ensured by the 1'23 motorshaft '16 carrying a worm and meshing with a wormwheel "l'l keyed to a shaft 78: this shaft controls through a worm 79 the wormwheel 66; another shaft 81 carrying said worm wheel is provided with a worm 82 engaging the worm wheel 68 carried by bearings secured to This wheel 83 controls a worm 84 cooperating with, the large toothed wheel 85 keyed to the control shaft 71. This wheel 65 moves integrally with another toothed wheel 66 controlled through a suitable gearwork and a ton similar to that just described by an electric high speed electric motor 87 se for the shifting of the mirror.

It is apparent that if the said motor 87 is started it makes both wheels 85-86 revolve and the wheel 65 connected with the plate '74 through the nonreversible worm gear 84-85 carries the plate '74 along with it as it rotates. 1

- On the contrary when the shifting motor 6'! is inoperative it looks the two toothed wheels 85-66. 11' now the time control motor '15 la startedtheworm'uiscausedtorotateandis thereby constrained to move round the toothed 15 wheel 85 and carries along with it the plate 74 and the. tubular shaft '70.

As disclosed heretofore with reference to Fig. 5 the time-control motor 75 also provides the declination controLof the mirror. This is ensured by a suitable gearwork and transmission: the motor 75 controls a worm 88 engaging a worm wheel 89- keyed to the rod 90 disposed along the axis of the time shaft 70. The upper end of this rod is threaded at its upper end and engages a nut 91 suitably prevented from rotation and to which is pivotally secured a small rod 92 the free end of which is pivotally secured to the mirror 1. According to the diagram shown in Fig. 5, the transmission between the motor 75 of Fig. 12 and the worm 88 includes a clutch system 49 controlled by three coils 50, 51, 52. The motor drives in a permanent manner the pinion 59 which, through the action of the clutch 49 and the reversely moving pinions 60-61, drives the worm 88 in either direction or allows it to remain stationary'as explained hereinabove.

Figs. 13 and 14 show two forms of switches or circuit breakers. In Fig. 13 the two main and auxiliary gas-filled bodies 9394 are connected through the tubes 95 and 96 filled with a mass of mercury 97 the level of which is shown at 98 and 99. To the side of the tube 96 is disposed an electrode 100 in permanent communication with the mass of mercury and an electrode 101 which communicates with the mass of mercury as soon as the gases in the auxiliary space 93 are heated without the main space 94 being heated. Inside the main gas-filled space is a small blackened shaving of soft steel 102.

The switch shown in Fig. 14 is somewhat similar. The heat-sensitive chamber 104 is connected with the compensating chamber 105 through the tube 106 filled with mercury the level of which is at 107 and 108. To the side of the tube 106 are disposed an electrode 109, in permanent connection with the mass of mercury and an electrode 110 the communication of which with the mass is broken as soon as the space 104 is heated without the space 105 being similarly heated. As in the case of Fig. 4 a small shaving 111 of blackened soft steel is disposed inside the heat-sensitive chamber 104. This shaving has for its object in both forms of execution to absorb the solar rays and to heat the gas in which it is immersed through the heat thus stored in it. The same result would be accomplished by blackening the glass of the heat sensitive space. However the switch would in this latter case have a certain inertia as the solar heat must, before heating the inner gas, heat the glass wall. This glass though thin has obviously an enormous calorific capacity with reference to that of the gas which it is desired to expand. The cooling is also slow as glass, being a bad heatconductor, loses its heat only slowly.

This detrimental inertia is greatly reduced through the use of a heat absorbing metal part immersed in the gaseous medium because:

(a) The glass wall of the heat-sensitive space may be thin and transparent in this case;

(b) The shaving which may be flat or semicylindrical is of very thin metal not subject to being attacked by mercury; the metal should moreover have a small heat-storing capacity and not be subject to melting. We may use advantageously burnished steel in plates 0,03 m/m thick.

The working of the apparatus is as follows:

The solar energy instead of being absorbed by the reservoir wall, passes through it without heating it and falls on the metal shaving, part or disc which, being very thin and a good conductor of heat. becomes very speedily hot and is speedily cooled through the infra-red radiations emitted by it. The gas is thus heated and cooled through the agency of the small metallic part.

It should be noted that the use of such switches containing small discs are not limited to the automatic heliostat the application to which is only an interesting particular case. Our invention obviously covers all other possible applications of such thermostatic switches containing a small metal part. a

What we claim is:

1. Heliostat comprising a movable mirror, a shaft directed along the axis of the earth and carrying said mirror, an electric motor actuating said shaft, a relay actuated by the reflected'beam to adapt said shaft to the diurnal movement of the sun, said relay being formed by a receptacle with two zones filled with gas, a mass of mercury, forming an electrode, separating the two zones and a plate of blackened metal being arranged in the zone subject to the heating action of the solar rays, means to vary the inclination of the mirror on the shaft which carries it, a relay actuated by the reflected beam to adapt this variation to the declination movement of the sun.

2. In a heliostat according to claim 1, to reflect the control beam on the diurnal movement relay, an optical system giving an image of the sun, a narrow strip of mirror to receive this image and mounted on a shaft connected in rotation with the diurnal shaft of the mirror so as to maintain said narrow mirror strip in the meridian plane of the sun, said mirror strip being arranged so as to receive the image of the sun when, by reason 115 of the diurnal movement thereof, the reflected beam has shifted from the predetermined direction.

3. In a heliostat according to claim 1 to reflect the controlling beam on the diurnal movement relay, an optical system giving an image of the sun, a narrow mirror strip to receive this image and mounted on an axis connected in rotation to the diurnal mirror axis in such manner as to maintain said narrow mirror strip in the meridian plane of the sun, said mirror strip being arranged to receive the image of the sun when, through the diurnal movement thereof, the reflected beam has shifted from the predetermined direction and, for reflecting the control beam on the declination relay, a second optical system giving an image of the sun, two narrow mirror strips, prolonged, but of different focus and parallel with the mirror strip of the diurnal relay to carry these mirrors a shaft connected in rotation to the diurnal shaft to maintain the two said mirrors in prolongation in the meridian of the sun, these two mirrors being arranged in such manner that the image of the sun is formed between them when the principal mirror is suitably 1413 directed, and on one of them when, by reason of the setting movement of the sun, the direction of the reflected beam has deviated from that predetermined, two relays formed like the diurnal movement relay and placed at the focal points of the two said mirror strips.

4. In a heliostat comprising a movable mirror mounted on a shaft parallel with the axis of the earth, means for making this shaft subject to the diurnal movement of the sun, two auxiliary mirror strips arranged in such manner that one of them receives an image of the sun when-the beam reflected by the movable mirror has deviated from the predetermined direction, two relays sensitive to heat placed in the foci of these auxiliary mirrors, a motor controlled by these relays, three coils fed through these relays, a swivel plate arranged below the said coils which it serves as an armature and which can assume three difierent positions accordingly as one or the other of three groups of two coils is excited, a device permitting of varying the inclination of the principal mirror on the shaft parallel with the axis of the earth, a reversing clutch adapted to connect said device with the motor, and means permitting the three coil armature to control said clutch.

5. In a heliostat comprising a movable mirror mounted on a shaft parallel with the axis of the earth, a motor driving this shaft at low speed, means to start said motor when, by reason of the diurnal movement of the sun, the beam reflected by the mirror has deviated from the predetermined direction, means permitting the same mo-, tor to vary the inclination of the mirror on the shaft parallel with the axis of the earth according to the declination of the sun, a second motor adapted to rotate the shaft parallel to the axis of the earth with a relatively high speed, a first relay sensitive to heat arranged so as to receive the rays of the sun as soon as they appear, a second relay, means permitting of illuminating this second relay when the movable mirror is turned in the desired direction, means to connect these two relays to the second motor in such manner that it rotates as soon as the first relay is illuminated, and stops when, by reason of the rotation of the shaft parallel with the axis of the earth, the second relay is in its turn illuminated.

6. In a heliostat comprising a movable mirror, means to make this mirror subject to the diurnal movement and setting of the sun, an auxiliary source of light, means to direct the light from this source in a predetermined direction, a relay always exposed to the rays of the sun, means to illuminate said auxiliary source through this relay when, through the disappearance of the sun, this relay ceases to be illuminated.

I. Auto-regulator heliostat according to claim 1, comprising a fixed casing, a time shaft formed by a hollow sleeve at the interior of this casing, mounted parallel with the axis of the earth, a principal mirror pivoted to the end of this sleeve, a solid shaft arranged at the interior of this sleeve so as to rotate relatively thereto, a plate integral with said sleeve, a motor mounted on this plate, a toothed wheel integral with the solid shaft, an irreversible transmission formed of pinions and worms betwen the motor and said toothed wheel, a second toothed wheel integral with the solid shaft, a second motor arranged on the fixed casing, an irreversible transmission composed of pinions and worms between the second motor and this second toothed wheel, said arrangement permitting the first motor, when it 50 is actuated, to drive only the hollow sleeve, while the second motor, on rotating, drives the solid shaft and the hollow sleeve together, a threaded rod arranged at the interior of the hollow sleeve, a nut guided on said threaded rod, 2. rod pivoted 35 on the one hand on said nut and on the other at the edge of the mirror, a reversing clutch, means connecting said clutch to the first motor, means connecting said clutch to the threaded rod, means permitting the first motor to turn the threaded rod and vary the inclination of the mirror on the hollow sleeve parallel with the earth's axis, a first strip-shaped auxiliary mirror curved to conform to the arc of an ellipse, so disposed that the sun rays impinge on it when, according to the daily movement of the sun, the beam reflected by the main mirror has deviated from the predetermined direction; two heat sensitive switches so disposed that the sun rays reflected by said auxiliary mirror impinge on both 10 when the main mirror is conveniently adjusted according to the sun declination and only on one of them when the declination has varied, means to start the first motor when at least one of the switches is heated, means to control the reversing clutch by said switches in such a way that it remains in disconnecting position when both are heated and when both are not and that it comes into one of its connecting positions when one only of said switch is heated; a third heat sensitive switch disposed in a place always exposed to the sun rays, a second auxiliary elliptical mirror so disposed that it receives the solar rays reflected by the main mirror when the same is conveniently directed, a fourth heat sensitive switch disposed at the focus of said second auxiliary mirror, means to connect the third and fourth switches with the second motor in such a way that it starts when the third switch is heated and stops when, in consequence of the rotation of the time shaft, the fourth switch receives also the sun rays.

8. Heliostat comprising a movable mirror, a shaft carrying said mirror, an electric motor actuating said shaft, a relay actuated by the reflected beam and controlling said motor to adapt said shaft to the diurnal movement of the sun, means to vary the inclination of the mirror on the shaft which carried it, said means comprising an electrical motor, a relay actuated by the reflected 13C beam and controlling said motor to adapt this variation of the mirror inclination to the declination movement of the sun.

JACQUES MARIE ARTHUYS. ANDRE 13am. 

